f.
The Water Supply
For best operation of the incubator, sterilized distilled,
demineralized or de-ionized water should be used in the humid-
ity reservoir. Water purity should be in the resistance range of
50K Ohm/cm to 1M Ohm/cm, or a conductivity range of 20.0
uS/cm to 1.0 uS/cm. Refer to ASTM Standard D5391-93 or
D4195-88 for measuring water purity.
Distillation systems, as well as some types of reverse
osmosis water purity systems, can produce water in the quality
range specified. Tap water is not recommended as it may con-
tain chlorine, which can deteriorate the stainless steel. Tap
water may also have a high mineral content, which would pro-
duce a build-up of scale in the reservoir. High purity, ultra pure
or milli-q water is not recommended as it is an extremely
aggressive solvent and will deteriorate the stainless steel. High
purity water has a resistance of above 1M Ohm to 18M Ohm.
Even high purity water can contain bacteria and organic con-
taminants. Water should always be sterilized or treated with a
decontaminant, safe for use with stainless steel as well as safe
for the product, prior to being introduced into the humidity
reservoir.
The incubator is equipped with a liquid level float switch
that detects low water levels in the humidity reservoir and pro-
duces an alarm condition. As all applications do not require
humidity, this alarm can be disabled. To disable the ADD
WATER alarm, see Section 3.1a. If humidity is required in the
current application, press the Silence key on the control panel
to mute the alarm while the humidity reservoir is being filled.
Distilled or de-ionized water used in the humidity
reservoir must be within a quality resistance range
of 50K Ohm/cm to 1M Ohm/cm to protect and
prolong the life of the stainless steel. Use of water
outside the specified range will decrease the oper-
ating life of the unit and may void the warranty.
g. Filling the Humidity Reservoir
1. In-house “distilled” water supply
All incubators provide a connection for using an in-house
water supply. Connect a low pressure (not more than 30 PSI)
water line, equipped with a manual shut-off valve, to the inlet
fitting on the float valve reservoir. The 1/4” hose connection is
located on the rear of the incubator cabinet. With the water
turned on, a float valve inside the incubator regulates the water
level in the humidity reservoir. When the reservoir is full, a 10-
second audible tone is heard and the ADD WATER message no
longer displays.
2. Manual method
This fill system consists of a funnel attached to the side
duct sheet and tubing located inside the incubator. Disinfect the
funnel and rinse with sterile water before using. This funnel
may be moved to a preferred location by unscrewing the well
nuts and disconnecting it from the sidewall. Tighten the nuts
after relocation. The holes allotted for funnel use are slightly
larger and in a centralized area. See Figure 1-6.
To fill the reservoir, pour sterile distilled water (approxi-
mately 2.5 gallons) into the funnel. When the float switch trips,
a 10-second audible tone sounds and the ADD WATER mes-
sage no longer displays. Add 1 gallon after the 10-second tone
is heard.
3. Gravity feed method
An optional carboy water fill system is also available. The
carboy option kit includes an instruction sheet that details the
installation of the system.
h. Connecting the Unit to Electrical Power
See the serial tag on the side of the unit for electrical speci-
fications or refer to the electrical schematics at the end of this
manual.
Connect the incubator to a grounded, dedicated
circuit. The power cord connector is the mains
disconnect device for the incubator. Position the
incubator so the unit can be easily disconnected.
Plug the provided power cord into the power inlet connec-
tor on the back of the cabinet, then into the grounded, dedicated
electrical circuit.
The 3950 Series also has an internal outlet located on the
right side of the interior back wall. The outlet is to provide
power (230W maximum) to accessory equipment. This outlet is
not to be used when the temperature is above 40°C and the RH
more than 50%.
Model 3950/3951 ____________________________________________________________________Installation and Start-Up
1 - 4
Figure 1-6
